#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 1e5 + 7;
const int md = 1e9 + 7;
int n, q;
int p[N], d[N];
vector<int> g[N];
int best[N], best2[N];
int dp[N], dp2[N];
int sum = 0;
void dfs(int v) {
best[v] = best2[v] = -1;
dp[v] = dp2[v] = 0;
for (int u : g[v]) {
dfs(u);
if (dp[u] + d[u] > dp[v]) {
dp2[v] = dp[v], best2[v] = best[v];
dp[v] = dp[u] + d[u], best[v] = u;
} else if (dp[u] + d[u] > dp2[v]) {
dp2[v] = dp[u] + d[u];
best2[v] = u;
}
}
sum += dp[v] + dp2[v];
}
signed main() {
#ifdef LOCAL
freopen("input.txt", "r", stdin);
#endif
ios::sync_with_stdio(false);
cin.tie(0);
cin >> n;
p[0] = -1;
for (int i = 1; i < n; ++i) {
cin >> p[i];
g[p[i]].push_back(i);
}
for (int i = 1; i < n; ++i) {
cin >> d[i];
}
dfs(0);
cout << sum << "\n";
cin >> q;
while (q--) {
int v, add;
cin >> v >> add;
d[v] += add;
while (v != 0) {
if (v == best[p[v]]) {
sum += dp[v] + d[v] - dp[p[v]];
dp[p[v]] = dp[v] + d[v];
} else if (dp[v] + d[v] > dp[p[v]]) {
sum += dp[p[v]] - dp2[p[v]] + dp[v] + d[v] - dp[p[v]];
dp2[p[v]] = dp[p[v]], best[p[v]] = best2[p[v]];
dp[p[v]] = dp[v] + d[v], best[p[v]] = v;
} else {
if (dp[v] + d[v] > dp2[p[v]]) {
sum += dp[v] + d[v] - dp2[p[v]];
dp2[p[v]] = dp[v] + d[v], best2[p[v]] = v;
}
break;
}
v = p[v];
}
cout << sum % md << "\n";
}
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
2764 KB |
Output is correct |
2 |
Correct |
4 ms |
2808 KB |
Output is correct |
3 |
Correct |
2 ms |
2764 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
85 ms |
12188 KB |
Output is correct |
2 |
Correct |
75 ms |
10800 KB |
Output is correct |
3 |
Correct |
89 ms |
11236 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
537 ms |
14136 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
2764 KB |
Output is correct |
2 |
Correct |
4 ms |
2808 KB |
Output is correct |
3 |
Correct |
2 ms |
2764 KB |
Output is correct |
4 |
Correct |
85 ms |
12188 KB |
Output is correct |
5 |
Correct |
75 ms |
10800 KB |
Output is correct |
6 |
Correct |
89 ms |
11236 KB |
Output is correct |
7 |
Incorrect |
537 ms |
14136 KB |
Output isn't correct |
8 |
Halted |
0 ms |
0 KB |
- |